Distributed communication systems or networks are now widely used. Such communications systems may be widely distributed information sources such as local- or wide-area networks, corporate or military communication systems, or the world-wide computerized interactive communication system known as the internet. Such communication systems can be used to access remote information or computing resources. When using such systems, it is necessary to know the location or address of the information being sought or of the computing resource to be used, or the user must carry out a search procedure to locate the information. In the case of very large distributed systems which are not indexed, the search is so extensive or time-consuming that it may be impractical, and may therefore not be attempted.
There has been interest in the use of intelligent mobile agents for overcoming some of the problems associated with searches of distributed, possibly unindexed, data bases or computing resources. An intelligent mobile agent is a computer program which can independently or semi-independently perform tasks which the operator could not perform on his own because of the time or effort required for the task. For example, an intelligent mobile agent might be used to discover information autonomously, or under its own control, because the operator or user of the distributed communication system might not be aware of the existence of a source of useful information, or of its address if its existence were known. The mobile intelligent agent is a computer-type program characterized by the ability to move over the communication system from one computer to another while the program is "running"; in fact, it is necessary for it to do so in order to perform its tasks. This does not, of course, mean that the bit pattern of the program changes while it is in transit from one computer to the other, but rather means that, in performing its tasks or "running," the program moves its location from one computer to another. Intelligent mobile agents or "softbots" are described in the following references:
1) "Intelligent Agents: The First Harvest of Softbots Looks Promising", Sara Reese Hedberg, IEEE Expert. PA1 2) "Harnessing the World Wide Web", Jay Allen Sears, U.S. Advanced Research Projects Agency, IEEE Expert. PA1 3) "Intelligent Agents on the Internet: Fact, Fiction, and Forecast", Oren Etzioni and Daniel S. Weld, University of Washington, IEEE Expert. PA1 4) "AI on the WWW--Supply and Demand Agents", Carol Brown, Oregon State University; Les Gasser and Daniel E. O'Leary, University of Southern California; Alan Sangster, University of Aberdeen, IEEE Expert. PA1 5) "Telescript Technology: Mobile Agents", James E. White, General Magic, Inc., American Association for Artificial Intelligence.
One problem which has been found with the use of such mobile agents for seeking information on a distributed computing or knowledge base is that the capability of the agent is more or less related to the size or complexity of the program which embodies the intelligent mobile agent, so that a highly capable mobile agent, just like a highly capable computer program of any sort, tends to be very large in terms of the number of bytes which it contains. The length of time required to transmit the intelligent mobile agent from one computer to another over the communication system depends upon the bandwidth of the system in bits or bytes per second. It may not be practical to use a highly capable intelligent mobile agent, because the large size of such an agent requires excessive computer-to-computer transmission time. If the bandwidth of the distributed communication system can be controlled, then its bandwidth can simply be expanded in order to accommodate the desired mobile agents at the desired speed. Ordinarily, the communication system or data base is a given, and its bandwidth cannot be controlled. It should be noted here that limitations in the bandwidth of a part of a computer which interacts with the communication system will have the same effect, as to that computer, as a limitation of the bandwidth of the communication system itself; it is therefore desirable to use the highest possible speed modem at each computer site. Under bandwidth-limited conditions, the use of a highly capable intelligent mobile agent may result in excessive transmission time delays, and these directly impact the time required for the intelligent mobile agent to perform a search. The amount of time which is considered to be excessive may depend upon the information sought and its importance. If search time is irrelevant, a highly capable intelligent mobile agent may be used on a low-bandwidth distributed computing or network. Ordinarily, however, large transmission times are undesirable because of the resulting delays in receiving the search results, especially in those cases in which real-time information is sought. Thus, if a very complex search is required to find the desired information, a highly capable intelligent mobile agent capable of performing the search may be too large to be practical under given circumstances. The inability to quickly transmit highly capable intelligent mobile agents prevents full utilization of the resources of the communication system.
Improved methods are desired for transmitting highly capable intelligent mobile agents over communication systems interlinking distributed computing systems.